items that will always be variable costs:

it is a _cost of if it cost you more if you make or sell more:

fixed costs:

-total cost does not change with changes in the volume of activity (within the relevant range).
-the cost per unit WILL change as volume (number of units) changes. total
(the total amount may be different than expected; however, this will not be due to changes in the volume of units made or sold).

charges for a cell phone is $39.99 plus $.40 for each minute used for 400 minutes is an example of:

relevant range:

The range of activity where the assumption about cost behavior is valid.

Example: The company's fixed costs will remain fixed as long as
production greater than 1,000,000 units is not required.
If more than that must be produced, then a new facility with
higher facility costs and overhead costs will be required.

The company's fixed costs will change if they have to produce
more than 1,000,000 units. Up to 1,000,000 is the relevant range

utilities and sales person travels expenses are:

A cell phone for sales people and oil and parts for manufacturing machines are:

These costs could be fixed or mixed. This is determined by how the company plans to pay for the costs. If there is a set amount to be paid
every month it is fixed, if it varies by units made or sold, they are variable costs.